(1) Field of Invention
The present invention relates to a load-bearing apparatus, and more particularly to a passive exoskeleton onto which a load may be placed, with the weight of the load transferred from the passive exoskeleton to a ground surface, causing the passive exoskeleton to support at least a portion of the load.
(2) Background of Invention
Load bearing devices have long been known in prior art. For example, backpacks with frames have long been employed to reduce a load carried by an individual's shoulders. Although the backpack functions to distribute the load, the weight of the load is transferred to the individual's hips, forcing the individual to ultimately bear the burden of the load. Because of the necessity to bear the burden of the load, the amount of weight an individual may carry using a traditional backpack is limited.
Other examples of load-bearing devices include orthopedic devices such as canes, crutches, and walkers. Although orthopedic devices transfer the load to the ground, they generally are designed under an assumption that the user must be able to stand and carry his/her own weight. Many orthopedic devices require the user's upper torso to be continuously used and such devices generally are not useful when upper limbs must remain free and unoccupied.
Another example of an orthopedic device is disclosed in U.S. Pat. No. 6,015,076, issued to Pennington (“the Pennington patent”). The Pennington patent discloses a hip belt which reduces fatigue by bridging across muscles and nerves in the gluteal region. A drawback of devices made according to this particular prior art is that all of the weight is still carried by the individual's skeletal and muscular system.
In an effort to reduce the load placed on the user's skeletal and muscular system, powered exoskeletons have been proposed. Powered exoskeletons mimic the function of body joints by using actuators or artificial muscles. The actuators required for these exoskeleton concepts consume significant power, supplies for which are either difficult to produce or are currently unavailable. Additionally, the compact actuator (artificial muscle) technology has currently not progressed enough to make practical devices. As such, the development of a powered exoskeleton requires further developments in a variety of fields, including actuation, artificial muscles, and advanced energy storage. Given the current state of these technologies, powered exoskeletons may not be realized for decades to come.
In an effort to provide an exoskeleton without a power system, the applicant of the present invention previously devised a passive exoskeleton. The passive exoskeleton comprises a rigid body member for attaching proximate a portion of a user's body, a rocker pivotally attached with the body member, a sliding rod attached with the rocker, and a ground surface engage-able foot analog attached with the sliding rod. The rocker has both a load channel and a travel channel, while a load pin attached with the sliding rod travels between the load and travel channels as a user walks. As a user places a load on the body member and walks forward, weight of the load is transferred from the body member, through the rocker's load channel, onto the load pin and its sliding rod. Thereafter, weight from the load passes into the foot analog, causing the passive exoskeleton to support at least a portion of the load. Rocker stops are attached with the body member, such that when a user is in a full stride gait, the rocker continues its motion until it hits the rocker stops at the limit of its travel. The rocker stops aid the load pin in transferring between the load and travel channels at the appropriate times during the user's forward gait. Although functional for forward motion, the problem with such a configuration is that it does not work as well for backwards (i.e., reverse) motion. With a single load channel, the rocker stops alone are not sufficient to aid in transferring the load pin between the load and travel channels when a user is traveling backwards.
Thus, it can be appreciated that there exists a continuing need for a passive exoskeleton that permits a user to walk both forward and backwards, such that in either direction, the load pin travels between the load and travel channels at the appropriate times during a user's gait. The present invention substantially fulfills this need.